This grant will provide continued NIH support to maintain and enhance the Caribbean Primate Research Center (CPRC). The CPRC consists of three integrated facilities: (1) Cayo Santiago, a unique free-ranging island colony of rhesus monkeys (Macaca mulatta); (2) the Sabana Seca Field Station, the CPRC's headquarters located ten miles outside of San Juan that houses rhesus monkeys derived from the Cayo Santiago colony in various outdoor configurations for biomedical and behavioral studies that are not feasible on free-ranging animals; and (3) the CPRC Museum, located on the Medical Sciences Campus (MSC) in San Juan, that houses the CPRC Skeletal Collection, the world's largest and most important collections of nonhuman primate skeletons for anatomical, developmental, genetic and pathological research. As described in this application, the CPRC Program is organized into six Divisions: (1) primate Resources, (2) virology, (3) genetics, (4) reproductive biology, (5) behavioral neurosciences, and (6) skeletal biology. Funds are requested in this application to maintain and enhance the CPRC basic infrastructure, which is needed for the support of several biomedical research initiatives of national interest. This core grant will also allow CPRC to seek additional support for the other Divisions to launch collaborative research projects with mainland and international investigators. With continued NIH support, the CPRC will remain a significant national research resource and will be able to provide healthy monkeys of defined virological and genetic background to NIH-sponsored programs and to the scientific community at large.